BASS.NET API for the Un4seen BASS Audio Library

BassBASS_StreamCreateURL Method

BASS.NET API for the Un4seen BASS Audio Library
Creates a sample stream from an MP3, MP2, MP1, OGG, WAV, AIFF or plugin supported file on the internet, optionally receiving the downloaded data in a callback.

Namespace:  Un4seen.Bass
Assembly:  Bass.Net (in Bass.Net.dll) Version: 2.4.17.5
Syntax

public static int BASS_StreamCreateURL(
	string url,
	int offset,
	BASSFlag flags,
	DOWNLOADPROC proc,
	IntPtr user
)

Parameters

url
Type: SystemString
URL of the file to stream. Should begin with "http://", "https://" or "ftp://", or another add-on supported protocol. The URL can be followed by custom HTTP request headers to be sent to the server; the URL and each header should be terminated with a carriage return and line feed ("\r\n").
offset
Type: SystemInt32
File position to start streaming from. This is ignored by some servers, specifically when the file length is unknown, for example a Shout/Icecast server.
flags
Type: Un4seen.BassBASSFlag
Any combination of these flags (see BASSFlag):
BASS_SAMPLE_FLOATUse 32-bit floating-point sample data. WDM drivers or the BASS_STREAM_DECODE flag are required to use this flag in Windows. See Floating-point channels for more info.
BASS_SAMPLE_MONODecode/play the stream (MP3/MP2/MP1 only) in mono, reducing the CPU usage (if it was originally stereo). This flag is automatically applied if BASS_DEVICE_MONO was specified when calling BASS_Init(Int32, Int32, BASSInit, IntPtr, IntPtr).
BASS_SAMPLE_3DUse 3D functionality. This is ignored if BASS_DEVICE_3D wasn't specified when calling BASS_Init(Int32, Int32, BASSInit, IntPtr, IntPtr). 3D streams must be mono. The SPEAKER flags can not be used together with this flag.
BASS_SAMPLE_LOOPLoop the file. This flag can be toggled at any time using BASS_ChannelFlags(Int32, BASSFlag, BASSFlag). This flag is ignored when streaming in blocks (BASS_STREAM_BLOCK).
BASS_STREAM_RESTRATERestrict the download rate of the file to the rate required to sustain playback. If this flag is not used, then the file will be downloaded as quickly as the user's internet connection allows.
BASS_STREAM_BLOCKDownload and play the file in smaller chunks, instead of downloading the entire file to memory. Uses a lot less memory than otherwise, but it is not possible to seek or loop the stream; once it has ended, the file must be opened again to play it again. This flag will automatically be applied when the file length is unknown, for example with Shout/Icecast streams. This flag also has the effect of restricting the download rate.
BASS_STREAM_STATUSPass status info (HTTP/ICY tags) from the server to the DOWNLOADPROC callback during connection. This can be useful to determine the reason for a failure.
BASS_STREAM_AUTOFREEAutomatically free the stream when it ends. This allows you to stream a file and forget about it, as BASS will automatically free the stream's resources when it has reached the end or when BASS_ChannelStop(Int32) (or BASS_Stop) is called.
BASS_STREAM_DECODEDecode the sample data, without outputting it. Use BASS_ChannelGetData(Int32, IntPtr, Int32) to retrieve decoded sample data. The BASS_SAMPLE_SOFTWARE, BASS_SAMPLE_3D, BASS_SAMPLE_FX, BASS_STREAM_AUTOFREE and SPEAKER flags can not be used together with this flag.
BASS_SPEAKER_xxxSpeaker assignment flags.
proc
Type: Un4seen.BassDOWNLOADPROC
Callback function to receive the file as it is downloaded... = no callback.
user
Type: SystemIntPtr
User instance data to pass to the callback function.

Return Value

Type: Int32
If successful, the new stream's handle is returned, else 0 is returned. Use BASS_ErrorGetCode to get the error code.
Remarks

Use BASS_ChannelGetInfo(Int32, BASS_CHANNELINFO) to retrieve information on the format (sample rate, resolution, channels) of the stream. The playback length of the stream can be retrieved using BASS_ChannelGetLength(Int32, BASSMode).

When playing the stream, BASS will stall the playback if there is insufficient data to continue playing. Playback will automatically be resumed when sufficient data has been downloaded. BASS_ChannelIsActive(Int32) can be used to check if the playback is stalled, and the progress of the file download can be checked with BASS_StreamGetFilePosition(Int32, BASSStreamFilePosition).

When streaming in blocks (BASS_STREAM_BLOCK flag), be careful not to stop/pause the stream for too long, otherwise the connection may timeout due to there being no activity and the stream will end prematurely.

When streaming from Shoutcast servers, metadata (track titles) may be sent by the server. The data can be retrieved with BASS_ChannelGetTags(Int32, BASSTag). A sync can also be set (using BASS_ChannelSetSync(Int32, BASSSync, Int64, SYNCPROC, IntPtr)) so that you are informed when metadata is received. A BASS_SYNC_OGG_CHANGE sync can be used to be informed of when a new logical bitstream begins in an Icecast/OGG stream.

When using an offset, the file length returned by BASS_StreamGetFilePosition(Int32, BASSStreamFilePosition) can be used to check that it was successful by comparing it with the original file length. Another way to check is to inspect the HTTP headers retrieved with BASS_ChannelGetTags(Int32, BASSTag).

Custom HTTP request headers may be ignored by some plugins, notably BASSWMA.

Platform-specific: On Windows and Windows CE, ACM codecs are supported with compressed WAV files. Media Foundation codecs are also supported on Windows 7 and updated versions of Vista, including support for AAC and WMA. On iOS and macOS, CoreAudio codecs are supported, including support for AAC and ALAC. Android's media codecs are also supported, including support for AAC. In all cases, the OS's codecs are only tried after BASS's built-in decoders and any plugins have rejected the file. Built-in support for IMA and Microsoft ADPCM WAV files is provided on Linux/Android/Windows CE, while they are supported via ACM and CoreAudio codecs on Windows and macOS/iOS.

On iOS 7 and above, this function can be used to open files in the iPod Library ("ipod-library://" URLs). The offset and proc and user parameters are ignored then, as are the BASS_STREAM_RESTRATE and BASS_STREAM_BLOCK and BASS_STREAM_STATUS flags. The files are played using CoreAudio codecs and BASS does not have direct access to the files itself, so the only tags available from BASS_ChannelGetTags(Int32, BASSTag) will be BASS_TAG_CA_CODEC tags; the MPMediaItem properties could be used to get more info.

ERROR CODEDescription
BASS_ERROR_INITBASS_Init(Int32, Int32, BASSInit, IntPtr, IntPtr) has not been successfully called.
BASS_ERROR_NOTAVAILOnly decoding channels (BASS_STREAM_DECODE) are allowed when using the "no sound" device. The BASS_STREAM_AUTOFREE flag is also unavailable to decoding channels.
BASS_ERROR_NONETNo internet connection could be opened. Can be caused by a bad proxy setting.
BASS_ERROR_ILLPARAMurl is not a valid URL.
BASS_ERROR_PROTOCOLThe protocol in url is not supported.
BASS_ERROR_SSLSSL/HTTPS support is not available. See BASS_CONFIG_LIBSSL.
BASS_ERROR_TIMEOUTThe server did not respond to the request within the timeout period, as set with the BASS_CONFIG_NET_TIMEOUT config option.
BASS_ERROR_DENIEDA valid username/password is required.
BASS_ERROR_FILEOPENThe file could not be opened.
BASS_ERROR_FILEFORMThe file's format is not recognised/supported.
BASS_ERROR_UNSTREAMABLEThe file cannot be streamed. This could be because an MP4 file's 'mdat' atom comes before its 'moov' atom.
BASS_ERROR_NOTAUDIOThe file does not contain audio, or it also contains video and videos are disabled.
BASS_ERROR_CODECThe file uses a codec that's not available/supported. This can apply to WAV and AIFF files, and also MP3 files when using the "MP3-free" BASS version.
BASS_ERROR_FORMATThe sample format is not supported by the device/drivers. If the stream is more than stereo or the BASS_SAMPLE_FLOAT flag is used, it could be that they are not supported.
BASS_ERROR_SPEAKERThe specified SPEAKER flags are invalid. The device/drivers do not support them, they are attempting to assign a stereo stream to a mono speaker or 3D functionality is enabled.
BASS_ERROR_MEMThere is insufficient memory.
BASS_ERROR_NO3DCould not initialize 3D support.
BASS_ERROR_UNKNOWNSome other mystery problem!

Platform-specific

Away from Windows, all mixing is done in software (by BASS), so the BASS_SAMPLE_SOFTWARE flag is unnecessary. The BASS_SAMPLE_FX flag is also ignored.

On Windows and Windows CE, ACM codecs are supported with compressed WAV files. Media Foundation codecs are also supported on Windows 7 and updated versions of Vista, including support for AAC and WMA. On iOS and OSX, CoreAudio codecs are supported, including support for AAC and ALAC. Media Foundation and CoreAudio codecs are only tried after the built-in decoders and any plugins have rejected the file. Built-in support for IMA and Microsoft ADPCM WAV files is provided on Linux/Android/Windows CE, while they are supported via ACM and CoreAudio codecs on Windows and OSX/iOS.

Examples

Bass.BASS_Init(-1, 44100, BASSInit.BASS_DEVICE_DEFAULT, IntPtr.Zero);
int channel = Bass.BASS_StreamCreateURL("http://someurl.com:8000", 0, 
                   BASSFlag.BASS_DEFAULT, null, IntPtr.Zero);
Bass.BASS_ChannelPlay(channel, false);
See Also

Reference